Trimmer mechanisms for sewing machines



April 30, 1957 R. P. GRAHAM 2,790,405

TRIMMER MECHANISMS FOR SEWING MACHINES 7 Filed Feb. 27. 1952 4 Sheets-Sheet 1 y' 4 INVENTOR.

R1 chard 1. firahmn WITNESS= 4/ -5 ATTORNEY April 30, 1957 R. P. GRAHAM I 2,790,405

TRIMMER MECHANISMS FOR SEWING MACHINES Filed F6b. 27. 1952 4 Sheets-Sheet 2 i! 39 65 I 29 33 e0 20 INVENTOR.

Y Richard Gmlzam WITNESS- z P ATTORNEY April 30, 1957 R. P. GRAHAM TRIMMER MECHANISMS FOR SEWING MACHINES Filed Feb. 27. 1952 4 Sheets-Sheet 5 INVENTOR. Richard Graham ATTORNEY April 30, 1957 R. P. GRAHAM 2,790,405

TRIMMER MECHANISMS FOR SEWING MACHINES Filed Feb. 27. 1952 4 Sheets-Sheet 4 I INVENTOR. BY Richard Graham ATTORNEY United States Patent TRIMMER MECHANISMS FOR SEWING MACHINES Richard P. Graham, Stratford, Coun., assignor to The Singer Manufacturing Company, Elizabeth, N. J., a corporation of New Jersey Application February 27, 1952, Serial No. 273,603

Claims. (Cl. 112-123) The present invention relates to sewing machines and has for a primary object to provide an improved trimmer actuating mechanism for sewing machines.

More specifically, the present invention has for an-object to provide a trimmer actuating mechanism in which the stroke of the trimmer blade can be readily adjusted to correspond to any changes in the stitch length as determined by the setting of the feed-advance mechanism. This has been accomplished by providing a common actuating means for both the trimmer and feed-advance mechanism. Thus, any variations in the stitch length automatically results in a corresponding variationin the stroke of the trimmer. This results in a tendency to prolong the useful life of the trimming blade by varying the cutting-edge travel of the movable blade relative to the ledger blade.

It is a further object of the present invention to provide a combined trimmer actuating and feed-advance mechanism composed of relatively simple mechanical expedients that are practical and economically feasible.

Having in mind these and other objects that will be evident from an understanding of this disclosure, a presently preferred embodiment of the invention is hereinafter set forth in such detail as to enable those skilled in the art to readily understand the function, operation, construction and advantages of it when read in conjunction with the accompanying drawings in which: i

Fig. 1 is a vertical sectional view longitudinally of a sewing machine that embodies the present invention, with the certain parts of the machine broken away to illustrate the invention more clearly.

Fig. 2 is a sectional view taken substantially on, the

.line 2--2 of Fig. l, with the take-up guard of theme.-

line 44 of Fig. 1.

Pig. 5 is a sectional view taken substantially on the line 5-5 of Fig. 3 that illustrates a detail of the machine.

Fig. 6 is a sectional view taken substantially on the line 66 of Fig. 3.

Fig. 7 is a diagrammatic view of the trimmer mechanism showing it in its extreme upper and lower positions.

The sewing machine illustrated in the drawings comprises a substantially rectangular bed 1 having a standard 2 rising from the right rear corner thereof and carrying a bracket-arm 3 terminating in a head 4. As shown, the machine selected as a preferred embodiment of the invention is particularly adapted to do edge stitching and consequently the bracket-arm 3 has been made very 'stantially vertical and the needle-bar 5 and resser-oar 6 will reciprocate vertically. By means of the inclined ice arm, there is provided a maximum of usable work-support area thus facilitating manipulation of the work while maintaining minimum dimensions of the bed 1. 'Journaled' in suitable bearings 7 and 8 located respectively in'an'end wall of the bracket-arm 2 and in a boss 9 integral with a side wall of the bracket-arm, is a rotary actuating shaft 10 having a combined belt-pulley and hand-wheel 11 secured to that end thereof that projects through the end wall of the bracket-arm. At its opposite end, the shaft 10 carries a counterbalanced crank 12 having a crank-pin 13 embraced by one end of a link 14 which, at its other end, has journaled therein a stud 15 secured to the needle-bar 5 for actuating the same. There is provided a single rotary take-up, generally indicated at 16, which is substantially the same as that disclosed 'and claimed in the co-pending applica- .tion of Van Wagener et al., Serial No. 189,528, to which reference may be made for a more complete description thereof. A take-up guard 17 is secured to the end of the head 4 in the usual manner.

Depending from the under side of the bed 1 are walls 18 and 19 arranged longitudinally of the machine adjacent the front and back thereof, respectively. There are two legs 20 formed integral with the walls 18 and 19 at the one end thereof, and a single leg 21 formed integral with a boss 22 that depends from the bedl. The boss22 carries a rotary-hook assembly 23 and a bearing-sleeve 24. The hook-assembly as employed in this preferred embodiment of my invention is substantially the same as disclosed in the U. S. patent of Kessler, No. 2,441,937, May 18, 1948, to which reference may be had for a more complete description thereof. It is sufficient for the present disclosure to point out that the hook-assembly 23 includes an outer bearing-bushing 25 secured in a suitable aperture 26 drilled longitudinally in the boss 22 and having journaled therein a shaft 27 carrying a gear 28 at one end and a rotary-hook 29 at the other end, which hook is adapted to cooperate with a needle 30 carried by the needle-bar 5 in the formation of stitches in the usual manner. It will be noted that the outer diameter of the bearing-bushing 25 is larger than that of the gear 28, so that the hook-assembly 23 can be inserted in and withdrawn from the aperture 26 in the boss 22 as a unit.

The bearing sleeve 24 is secured in a suitable aperture 31 formed in the boss 22 and disposed parallel to the aperture 26. Journaled in the sleeve 24, by bearings 32, is a feed-lift shaft 33 that has its one end eccentrically reduced to form a crank-pin 34, and at its other carries a gear 35 having a hub portion 36 through which extends a set screw 37 that releasably secures the gear to the shaft 33. By removing the gear 35 from the shaft 33, it will be seen that the bearing sleeve and the enclosed shaft and bearing can be withdrawn from the aperture 31 as a unit, and conversely, these elements may be inserted into the aperture 31 after which the gear 35 may be secured to the shaft 33.

The gears 28 and 35 are enclosed by integral walls depending from the bed 1 which define a lubricant chamber 38 and which include an end wall 39 (see Fig. 2) formed as an integral downward extension of the wall 19 adjacent the leg 20, an end wall 40 opposed to the end wall 39, a side wall 41 that includes one face of the boss 22, and a side wall 42 opposed to the side wall 41. The bottom of the lubricant chamber 38 is closed by a cover-plate 43. I

Formed in a boss 44, integral with the side wall 42 and depending from the bed 1, is an aperture 45 in which is removably secured a metallic bearing-bushing 46. To prevent oil within the-lubricant chamber 38 from leaking qut;tl1rough the joint between the bushing- 46 and the tersunk portions49 at.;the end ,ofa, bore,jbushing 46. Journaled in the bot-e550 and;hear,rngs AS jis a shaft 51 that carries agear 52,.which is rsrnaller-in eter than the .bearing46, lPon that end locatedlw lubricant chamber 38and a grooved ;pulley; 53;uponthe other end. Acliphelt 54 is .entrainediabout thepu1ley' 53 and a similar, pulley .55.secur.ed .to: the; shaft: 10.

,With reference. .tosFigs. 3 and 4,,itnwill;begseen.i that the. gears 28,, 35,. and.-52 are arrangedsto-trotateina ver .tical planevandztheirxaxespoftrotation lie .substantiallyqin ahorizoutal plane; Thetgears are thusin'nneshin a'l-series relationship, it e.,. the geari. 52,..which. isrthe driving gear and which receives powerithrough. the .belt';54 from thatsupplied tothe driven pulley ll ldrivesathengeaiz.35

which in. turn. drives the;.g'ear. 28. T-hap'ulleys 53mm! .55. and.the.gears 52 andiSS. each have afoneeto-one ratio, Iwhile vthergears.; ahd28 ihave, autwodo-one ratio-so that the hook willbeoperated at twice the Lspeed--of the .other mechanisms inrthe usual manner.

Thelgears in ;the lubricant chamber '38 are automatitcally lubricated by the oil in the chamber: which -issup- .plied at least to the point wherethe gears35and 52 will gears 28 and 52 are formed as parts ofsubassemblies that can be readily inserted into'thei-r proper-positions in a preassembled condition which eliminates the time consuming-task of assembling'them in position. 'The gear 35 is securedto-tthe shaft 33 in positionwvhich isdone before either-of the=other two'gears areinserted.

The-feeding mechanism ofthe-illustrated machine comprises a feed-dog'56-which,- in the-usual manner, coacts with apresser-foot 57 secured to the presser-bar' 6. The feed-dog iscarricd-at one end of a-feed-bar 58'pivoted at 't-he other end toa feed-advance rocker generally designated at 59 which'is of conventionalconstruction. Feed-lift movements are imparted to'the'feed-bar byv a link '60 pivoted thereto as by a screw 61, which link embraces the eccentric reduced end-34 offihe ;shaft '33. The rocker59 is secured to a shaft-62iournaleddnjsmtable bearing-bushings intv'vo bosses 63 andfiidepiariding from'the-bed-11 'adjacent the wall 19. -Os'cillationis iniparted to ithe 'shaft' 62 and consequently to the."rocker-;5 9 which effects the feed advance and re'turn movements of thefeed-ba-n by-a link 6S seeured to the-shaftat one'end jand pivotally connected at-the otherendqto one mint another-link 66. At its upper end, the linkodembraces a wrist-pin--67 secured to one end of an-anehor link" which, at its other-end, pivotally'embraces a stud 69, one end 70 of-which is embedded -in .a'boss {71 integralwith the-thead' lof the machine. A collar 72 prevents thedink 68 from coming off the stud 69. The forked lower end of a pitman 73 embraces the wrist-pin 67-on opposite sides of link. The pitrnan 73, at its upper end, terminates in a strap 74 that embraces an eccentric 75 formed. as an element of an adjustable eccentric-76 such as disclosed in the 'U; S. patent of'Myers, No. 2,128,031, to which patent reference may-be had for a more completemnden standing of the details thereof. It is suflicient for'purposes of the present disclosure to point out that-there.- centricity "of the eccentric 75 relative to the shaft mean be varied by depressing the spring-biased detent- 77 which releas'esthe ecc'entric'for rotation-of the shaft 10 r'elative thereto anddocks it in a stationary positionjtand then turning the shaft l fl' by-the' ha'nd -wheel' 11.

'f'The trimming mechanism is-"sim'ilar to that" disclosed in the cop'endin'g U. Si pateiifapplication of' Breul g s'eriei' gases-a No. 140,481 filed January 25, 1950 and is mountedupon a guide pin 77 press-fitted into an aperture 78 in the head 4. Slidably mounted, on the pin 77 is a sleeve 79 carrying a laterally projecting arm 80 terminating in 'a 5 bifurcated end 81 that slidably embraces a secondary guide pin 82 press-fittedintorangaperture 83 in the head 4.

A slot 84 is cut intothe arm 8 9 adjacent the bifurcated end 81 and a-screw 85 isrprovidedthat-projects through from one side of the slot and is threaded into the opposed 10 --side,--.whereby an adjustment of; the: opposed .sides toflthe slot relative toeach othermaynbe obtained, which, of

course, spaces the bifurcations-at the end 81--so-that-'-they will .close1y butslidably embraceuthe sides. of the :guide pin'82.

Secured to the arnt80 bysmeans ot a'screw 86 projecting through an elongated slot 87 formed in a horizontal leg 88 thereof, which screw holds said leg against a seat qforrned onsaidarm, :is .an angle-bracket .89-comprising, tin-additiontofithe leg 88,21 verti-calcleg--90:depending from 20 a horizontal1leg;=91- arranged at a right angleto the leg 88. ;-A,trimmer blade 92. .isremovably and iadjustably secured; to the lug190 by. screws-93,.and.;is adapted nsto jcooperatewith a ledger ,bladezltlucarried by thethroat- .plate, 101, to sever the work adjacent the point of stitch 25 formation. .;It will be'seen Q'Fig. 3) that-thecutting-edge -pf--the-blade 92-is slanted with respect toithe blade 100 so thattherenwill' be progressive: contact betweenthem. -Yertical' reciprocation is imparted. to the cutter blade ;;by atogg-le linkage similar to that disclosed and claimed 30 -inrthe U. S.-::patent.of Pin'kvoss, No. 2;202,599, and-corn- ;prising a' link"94 provided with a hub 95 whichis'ur- -.rounds a pivot bolt 96that also projects through an aperture in the arm 80. The link 94, at the 'endopposite -from Illelllllb'QS, embraces a knuckle-pin 97 which is 5 'lalsoengaged by the bifurcated end of alink 98 connected :at'its oppositeend to the wrist-pin 67. The links 94 and .98 lconstituteatoggle which, when in-the normal operative-position as illustrated in the drawings, is beyond dead center positionand'locked by a releasable-detent-(net 40 shown) toform a rigid connection between the wrist-pin i67 i.a'ndspivot pin'96, whereby the oscillation of the wristtpinx67 is transmitte'dto the pivot 96 and consequently torthe blade' 92. To break the toggle connection, there is provided a thumbrpiece 99 integral with the hub 95, 4 whichcan-be'depressed to release the detent and rotate :thehub about its pivot-96 and thus move the link 94, knuckle-pi'n't97 and link 98 to theother'side 'of its dead center position. With the toggle broken, the'osc'illation of the wrist pin-67 is-taken up in the knuckle-pin 97 and 59 is no -longertransmittedto thepivot 96, thus disabling the trimmer mechanism, which is held in a'retracted po's'i- -tion" -by a-spring *(notshown) 7 From the above, it-will be-evident that,when'thetoggle is 'locked', as the shaft 10 rotates, the adjustable eccentric 55 76 rotated therewith will impart substantially'vertical 're- 'ciproc'ation to the 'pitman 73 through the eccentric 75, 'which' in turn, oscillates the wrist-pin 67 confined to motion in a single path by the anchor link 68. The oscillationof the wrist-pin 67 is transmitted to the feed-advance and -return mechanism by the link 66 and to the trim- -niermechanism by the toggle links 94' and 98. Fig. 7 which is a schematic drawing of the elements, and-in which the eccentric is set for maximum strokes ofth'e feed mechanism and trimmer, the posit-ion of the ele- 55 merits when the trimmer is in its extreme upper position "is illnstr-ated' in full lines while that position in which the-trimmer is in'its extreme lower'pos'ition is-illustrated 5i dotted-lines. Itwillbe' understoodthat'anadjustnient of the eccentricfid relative to the shaft- 10 in-stich" a 79 'manner' as' toreduceor increase the eccentricity'will' accordingly -shorten or lengthen both the feeding stroke and the clitting';stroke simultaneously and-thus maintain corresponding" motions-between the two.

Numerous-alterations of the structure herein disclosed 75 will suggest themselves to those skilled imthe ant #Hbwever,rit is to be understood that the present disclosure relates to a preferred embodiment of my invention which is for purposes of illustration only and not to be construed as a limitation thereof. All such modifications which do not depart from the spirit of my invention are intended to be included within the scope of the appended claims.

Having thus set forth the nature of the invention, what I claim herein is:

1. In a sewing machine having a bed, a standard, and

an overhanging bracket-arm, stitch-forming mechanism,

feeding mechanism comprising a feed-dog and feed-advance actuating mechanism for imparting a work-advance stroke to said feed-dog to advance the work past said stitch-forming mechanism, trimmer mechanism adapted to sever the work adjacent the point of stitch formation, including a stationary ledger blade and a movable trimming blade, a rotary shaft journaled in said bracket-arm, an adjustable eccentric secured to said shaft, a movable element, means for confining said element to motion in a predetermined path, a pitman operatively associated with said eccentric and said element whereby motion is transmitted to said element from said eccentric through said pitman, operative connections between said element and said feed-actuating mechanism to impart feedadvance movements to said feeding mechanism,'and operative connections between said element and said trimmer mechanism including a manually breakable toggle linkage to impart work-severing movements to said trimming blade when said toggle is locked and to disable said trimming blade when said toggle is broken.

2. In a sewing machine having a frame including a bed, a standard, and an overhanging bracket-arm terminating in a head portion, a needle-bar slidably mounted in said head, and cooperating stitch-forming mechanism journaled in said bed, feeding mechanism comprising a feed-dog and feed-advance actuating mechanism for imparting a work-advance stroke to said feed-dog to advance the work past said stitch-forming mechanism, trimmer mechanism adapted to sever the work adjacent the point of stitch formation including a stationary ledger blade carried by said bed and a trimming blade slidably mounted in said head, an anchor link pivoted at one end on a horizontal axis to said frame, a wrist-pin secured to theopposite end of said link and thereby confined to motion in a predetermined path, selectively variable drive means for imparting motion to said wrist-pin, operative connections between said wrist-pin and said feedactuating mechanism to impart feed-advance movements thereto, and operative connections between said wrist-pin and said movable trimming blade including a link extending through the bottom wall of said head to impart work-severing movement-s to said trimming blade.

3. In a sewing machine, stitch-forming mechanism, feeding mechanism comprising a feed-dog and feed-advance actuating mechanism for imparting a work-advance stroke to said feed-dog to advance the work past said stitch-forming mechanism, trimmer mechanism adapted to sever the work adjacent the point of stitch formation including a stationary ledger blade and a movable trimming blade, a wrist-pin, an anchor link confining said wrist-pin to motion in a predetermined path, selectively variable drive means for imparting motion to said wristpin, operative connections between said wrist-pin and said feed-actuating mechanism to impart feed-advance movements to said feeding mechanism, and operative connections between said wrist-pin and said trimming mechanism to impart work-severing movements to said trimming blade.

4. In a sewing machine having a bed, a standard, and an overhanging bracket-arm, feeding mechanism comprising a feed-dog and feed-advance actuating mechanism for imparting a work-advance stroke to said feed-dog to advance the work past a stitch-forming mechanism, trimmer mechanism adapted to sever the work adjacent the point of stitch formation, including a stationary ledger; blade and a movable trimming blade, a movable element,

means for confining said elementto motion in a pre determined path, a rotary shaft journaled in said bracket-. arm, a rotary actuator secured to said shaft for imparte and said trimmer mechanism to impart work-severing movements to said trimming blade, a bed-shaft journaled in said bed substantially parallel to said arm-shaft, drive connections between said bed-shaft and said arm-shaft, and operative connections between said bed-shaft and said feeding mechanism to impart feed-lift movements to said feeding mechanism.

5. In a sewing machine having a bed, a standard, and an overhanging bracket-arm, feeding mechanism comprising a feed-dog and feed-advance actuating mechanism for imparting a work-advance stroke to said feed-dog to advance the work past astitch-forming mechanism, trimmer mechanism adapted to sever the work adjacent the point of stitch formation, including a stationary ledger blade and aimovable trimming blade, a movable element, means for confining said element to motion in a predetermined path, a rotary shaft journaled in said bracket-arm, a rotary actuator secured to said shaft for imparting motion to said element, operative connections between said element and said feed-actuating mechanism to impart feed-advance movements to said feeding mechanism, and operativetconnections between said element and said trimmer mechanism to impart work-severing movements to said trimming blade, a lubricant chamber depending from said bed, a bed-shaft journaled in and extending through one wall of said lubricant chamber, drive connections between said arm-shaft and said bedshaft, a feed-shaft journaled in and extending through one wall of said lubricant chamber, operative connec tions between said feed-shaft and said, feeding mechanism to impart feed-lift movements to said feeding mechanism, and meshing gears secured to said feed-shaft and bed-shaft within said lubricant chamber.

6. In a sewing machine having a bed, a standard, and an overhanging bracket-arm, a stitch-forming mechanism, feeding mechanism comprising a feed-dog and feed-advance actuating mechanism for imparting a work-advance stroke to said feed-dog to advance the work past said stitch-forming mechanism, a movable element, means for confining said element to motion in a predetermined path, a rotary arm-shaft journaled in said bracket-arm, a rotary actuator secured to said arm-shaft, operative connections between said rotary actuator and said element to impart motion to .said element, operative connections between said element and said feeding mechanism to impart feed-advance movements thereto, a lubricant chamber depending from said bed, a bed-shaft journaled in and extending through a'first side wall of said lubricant chamber, drive connections between said arm-shaft and said bed-shaft, a feed-shaft journaled in and extending through a second side wall of the lubricant chamber, operative connections between said feed-shaft and said feeding mechanism to impart feed-lift movements to said feeding mechanism, and meshing gears secured to said feed-shaft and bed-shaft within said lubricant chamber.

7. A sewing machine having work feeding mechanism including a work advancing feed dog, feed lift ;mechanism for imparting rising and falling motions to said feed dog, feed advance mechanism for imparting advance and return motions to said feed dog, trimming mechanism including a stationary ledger blade and a complemental and relatively movable trimming blade, having progressively cooperating cutting edges whereby the work severing stroke of the trimming mechanism will be varied in accordance with the variations in the relamenace-- tite iiibtioix lifivveeniisaid ftrimming blade and led ent -an -actu'ating elemenuadjustable means :f or rims-1 parti'n variable actuation to said actuating:elernent and operative connect-ions separately connecting said: actuate ing -element with said trimming mechanisrrrendstwith: said feca -advance mechanisnr tor imparting work' adr vanein'g niove'ment -to said feed 'do'g and reeiprocatory movement i to -saidmovable trimming bladei' 8." 1h a sewing machine having -a bedy-astandard; and

an over hanging bracket arm, complement'al' stitchl formingmehanismmounted insaid-bed and bracket arm, feedingmechanism-mounting in' 'said' bed y and: comprising a: feed 'dog; feed lift meehanism forimparting rising and falling motions to said feed dog;and feediadvance mechanism for irnparting advance andreturn moti'ons to: said feed dog, trimming mechanism -adapted -to-sever-the work adjacent to the point of -stiteh formation; and including a stationary ledg'e'r blade ancl a movable 'trimmingt blade having progrssively' cooperating cutting edges whereby the work severing' stroke of the trimming: mechanism wil l= 'be-*varied in accordance with the. variations in the. relative"motion between sa'id trimming: blade and ledger.- i

bladej alrotary shaftlijournaled -in said bracket arm, a rotary actuator -0n-saidshaft, a movable element, means for confini'ng said element-to motion in a predetermined path; operative connections'ibetween said rotary actuator and said-element for imparting rnotion to :said element,

operativeconnections betWeensaidelement and said .feed aflvance nechanism' to impart actuation to 'saidfeed dog,

and 'o'perative-connections between said element and said trimming mechanism to impart actuation tosaid movable trimmingbiad an overhanging bracket arm co'mplementalstitch formadfacent-to the point of stitch formation and including a stationary ledgerbl'ade and a movable trimming blade having progressivelycooperating cutting edges whereby the work-*-severing' stroke of the trimming. mechanism will'be' varied "in-accordance with the variations in'the S relativeaniotiombetweenlsaid trimmingabladezand ledger-i; blade; a rotary; shaft ijournaleds ina said'rbraclget arrngi airs. adjustable: eccentric tonisaid shaft;- a movable .elementp meansiorconfining said element toamotionsin-taipres. determined tpathga a tpitman .-1 operati'vely: connecting saidadjustable: eccentric to said elementifon imp'artihghmoez. tion to said element upon rotation of said cccentric;.:op.. erative connections .between .said; element: and .saidv feed advance mechanism to impart actuation to; said. feedldog, and operatiye'.connectionstbetween 'saidzelerhent and said trimmin mechanismgto'impart 'actuationato said-movable-v trimming blade;

10: In asewingrmaehina stitchsaforming;mechanism; feedingmechanism-comprising.a feed d'og, feed lift meehanismforiimpartingflrising and fallingmotionssto said; feed. dog and I feed; advance; mechanism itor, imparting; ad-t. Vance: and; return motions;..-to;-said;-feed:;dog; trimming mechanism: adapted to severnthetzwo'rh adjacent-1o the. point. ofstitch formationrand. includinga stationary ledger. blade: and a movable, trimmings blade; havingfla: v cnt-,. ting"- edgeislanted with. respect to; theline of" motion between-saidblade'g: a: movable: element; means for-com fining. saidr-element'v to. .motioniqin predetermined path-,- selectivelyavariable. driven means; for impartingmotion to said element, operative; connections; between: saidele ment and. said iced advance mechanism; to; impart feed; advanceimovements tossaid feeding, mechanism, and. 0p: erative conne'cti-ons between said; element :and;,-said -moyable trimmingzblade; for; impartingworlc'severing movei mentsthereto.

References (litedsin the: file. ofthis fpatem.

N D STATES ATE T 1,200,989,: 7 Rontkeia -Oct.-10, -19.16j DEC. 1,75'135083" Christensen etal; Mar. 25-, 1930: 1,940,501 McCann Dec.- 19, 1933 2,128,031: Myers. Aug. 23, 1928,- 2,13-1,01-1 Vesconte-etal Sept-20,1938; 2,202,599 Pinkvossi May 28;, 19 40- 2,453 ,072"- Johnson; Nov 2, 194 8 2,507,470: Hirsch May 9, 1950 2,594,523 Urscheler Apr. 29, 1952 2,617,374. De Robertis Nov. 11, 1952 

